RFR: 8285700: [TreeTableView] graphic property of TreeItem is still visible after collapsing tree

Fri Jul 7 05:31:17 UTC 2023

In `TreeTableRowSkin`, graphic was not updated along with tree item update.

Made changes to update graphics of TreeTableView row in `updateTreeItem()` method.

Added options in monkey tester to add graphics and subnodes to `TreeTableView` rows.

-------------

Commit messages:
 - Fix TreeTableView graphic property issue

Changes: https://git.openjdk.org/jfx/pull/1172/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1172&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8285700
  Stats: 32 lines in 2 files changed: 31 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jfx/pull/1172.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1172/head:pull/1172

PR: https://git.openjdk.org/jfx/pull/1172